/*
 * Copyright (C) 2011 Patrik Akerfeldt
 * Copyright (C) 2011 Jake Wharton
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.lightsky.infiniteindicator.indicator;

import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.drawable.Drawable;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.ViewConfigurationCompat;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;

import cn.lightsky.infiniteindicator.R;

import static android.graphics.Paint.ANTI_ALIAS_FLAG;
import static android.widget.LinearLayout.HORIZONTAL;
import static android.widget.LinearLayout.VERTICAL;

/**
 * Draws circles (one for each view). The current view position is filled and
 * others are only stroked.
 * <p>
 * Thanks to : https://github.com/JakeWharton/Android-ViewPagerIndicator
 */
public class CircleIndicator extends View implements PageIndicator {
	private static final int INVALID_POINTER = -1;

	private float mRadius;
	private final Paint mPaintPageFill = new Paint(ANTI_ALIAS_FLAG);
	private final Paint mPaintStroke = new Paint(ANTI_ALIAS_FLAG);
	private final Paint mPaintFill = new Paint(ANTI_ALIAS_FLAG);
	private ViewPager mViewPager;
	private ViewPager.OnPageChangeListener mListener;
	private int mCurrentPage;
	private int mSnapPage;
	private float mPageOffset;
	private int mScrollState;
	private int mOrientation;
	private boolean mCentered;
	private boolean mSnap = true;

	private int mTouchSlop;
	private float mLastMotionX = -1;
	private int mActivePointerId = INVALID_POINTER;
	private boolean mIsDragging;
	private int mRealCount;


	public CircleIndicator(Context context) {
		this(context, null);
	}

	public CircleIndicator(Context context, AttributeSet attrs) {
		this(context, attrs, R.attr.vpiCirclePageIndicatorStyle);
	}

	public CircleIndicator(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		if (isInEditMode()) return;

		//Load defaults from resources
		final Resources res = getResources();
		final int defaultPageColor = res.getColor(R.color.default_circle_indicator_page_color);
		final int defaultFillColor = res.getColor(R.color.default_circle_indicator_fill_color);
		final int defaultOrientation = res.getInteger(R.integer.default_circle_indicator_orientation);
		final int defaultStrokeColor = res.getColor(R.color.default_circle_indicator_stroke_color);
		final float defaultStrokeWidth = res.getDimension(R.dimen.default_circle_indicator_stroke_width);
		final float defaultRadius = res.getDimension(R.dimen.default_circle_indicator_radius);
		final boolean defaultCentered = res.getBoolean(R.bool.default_circle_indicator_centered);
		final boolean defaultSnap = res.getBoolean(R.bool.default_circle_indicator_snap);

		//Retrieve styles attributes
		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CirclePageIndicator, defStyle, 0);

		mCentered = a.getBoolean(R.styleable.CirclePageIndicator_centered, defaultCentered);
		mOrientation = a.getInt(R.styleable.CirclePageIndicator_android_orientation, defaultOrientation);
		mPaintPageFill.setStyle(Style.FILL);
		mPaintPageFill.setColor(a.getColor(R.styleable.CirclePageIndicator_pageColor, defaultPageColor));
		mPaintStroke.setStyle(Style.STROKE);
		mPaintStroke.setColor(a.getColor(R.styleable.CirclePageIndicator_strokeColor, defaultStrokeColor));
		mPaintStroke.setStrokeWidth(a.getDimension(R.styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth));
		mPaintFill.setStyle(Style.FILL);
		mPaintFill.setColor(a.getColor(R.styleable.CirclePageIndicator_fillColor, defaultFillColor));
		mRadius = a.getDimension(R.styleable.CirclePageIndicator_radius, defaultRadius);

		Drawable background = a.getDrawable(R.styleable.CirclePageIndicator_android_background);
		if (background != null) {
			setBackgroundDrawable(background);
		}

		a.recycle();

		final ViewConfiguration configuration = ViewConfiguration.get(context);
		mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
	}

	public void setRealViewCount(int viewCount) {
		mRealCount = viewCount;
	}

	public void setCentered(boolean centered) {
		mCentered = centered;
		invalidate();
	}

	public boolean isCentered() {
		return mCentered;
	}

	public void setPageColor(int pageColor) {
		mPaintPageFill.setColor(pageColor);
		invalidate();
	}

	public int getPageColor() {
		return mPaintPageFill.getColor();
	}

	public void setFillColor(int fillColor) {
		mPaintFill.setColor(fillColor);
		invalidate();
	}

	public int getFillColor() {
		return mPaintFill.getColor();
	}

	public void setOrientation(int orientation) {
		switch (orientation) {
			case HORIZONTAL:
			case VERTICAL:
				mOrientation = orientation;
				requestLayout();
				break;

			default:
				throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL.");
		}
	}

	public int getOrientation() {
		return mOrientation;
	}

	public void setStrokeColor(int strokeColor) {
		mPaintStroke.setColor(strokeColor);
		invalidate();
	}

	public int getStrokeColor() {
		return mPaintStroke.getColor();
	}

	public void setStrokeWidth(float strokeWidth) {
		mPaintStroke.setStrokeWidth(strokeWidth);
		invalidate();
	}

	public float getStrokeWidth() {
		return mPaintStroke.getStrokeWidth();
	}

	public void setRadius(float radius) {
		mRadius = radius;
		invalidate();
	}

	public float getRadius() {
		return mRadius;
	}

	public void setSnap(boolean snap) {
		mSnap = snap;
		invalidate();
	}

	public boolean isSnap() {
		return mSnap;
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);

		if (mViewPager == null) {
			return;
		}
		final int count = ((RecyleAdapter) mViewPager.getAdapter()).getRealCount();
//        final int count = (PageAdapter)mViewPager.getAdapter().getCount();
		if (count <= 1) {
			return;
		}

		int longSize;
		int longPaddingBefore;
		int longPaddingAfter;
		int shortPaddingBefore;
		if (mOrientation == HORIZONTAL) {
			longSize = getWidth();
			longPaddingBefore = getPaddingLeft();
			longPaddingAfter = getPaddingRight();
			shortPaddingBefore = getPaddingTop();
		} else {
			longSize = getHeight();
			longPaddingBefore = getPaddingTop();
			longPaddingAfter = getPaddingBottom();
			shortPaddingBefore = getPaddingLeft();
		}

		final float threeRadius = mRadius * 3;
		final float shortOffset = shortPaddingBefore + mRadius;
		float longOffset = longPaddingBefore + mRadius;
		if (mCentered) {
			longOffset += ((longSize - longPaddingBefore - longPaddingAfter) / 2.0f) - ((count * threeRadius) / 2.0f);
//            longOffset += ((longSize - longPaddingBefore - longPaddingAfter) / 2.0f) - ((mRealCount * threeRadius) / 2.0f);
		}

		float dX;
		float dY;

		float pageFillRadius = mRadius;
		if (mPaintStroke.getStrokeWidth() > 0) {
			pageFillRadius -= mPaintStroke.getStrokeWidth() / 2.0f;
		}

		//Draw stroked circles
		for (int iLoop = 0; iLoop < count; iLoop++) {
			float drawLong = longOffset + (iLoop * threeRadius);
			if (mOrientation == HORIZONTAL) {
				dX = drawLong;
				dY = shortOffset;
			} else {
				dX = shortOffset;
				dY = drawLong;
			}
			// Only paint fill if not completely transparent
			if (mPaintPageFill.getAlpha() > 0) {
				canvas.drawCircle(dX, dY, pageFillRadius, mPaintPageFill);
			}

			// Only paint stroke if a stroke width was non-zero
			if (pageFillRadius != mRadius) {
				canvas.drawCircle(dX, dY, mRadius, mPaintStroke);
			}
		}

		//Draw the filled circle according to the current scroll
		float cx = mSnapPage % count * threeRadius;
//        float cx = (mSnap ? mSnapPage : mCurrentPage) * threeRadius;
//        if (!mSnap) {
//            cx += mPageOffset * threeRadius;
//        }
		if (mOrientation == HORIZONTAL) {
			dX = longOffset + cx;
			dY = shortOffset;
		} else {
			dX = shortOffset;
			dY = longOffset + cx;
		}
		canvas.drawCircle(dX, dY, mRadius, mPaintFill);
	}

	public boolean onTouchEvent(MotionEvent ev) {
		if (super.onTouchEvent(ev)) {
			return true;
		}
		if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {
			return false;
		}

		final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
		switch (action) {
			case MotionEvent.ACTION_DOWN:
				mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
				mLastMotionX = ev.getX();
				break;

			case MotionEvent.ACTION_MOVE: {
				final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
				final float x = MotionEventCompat.getX(ev, activePointerIndex);
				final float deltaX = x - mLastMotionX;

				if (!mIsDragging) {
					if (Math.abs(deltaX) > mTouchSlop) {
						mIsDragging = true;
					}
				}

				if (mIsDragging) {
					mLastMotionX = x;
					if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
						mViewPager.fakeDragBy(deltaX);
					}
				}

				break;
			}

			case MotionEvent.ACTION_CANCEL:
			case MotionEvent.ACTION_UP:
				if (!mIsDragging) {
					final int count = mViewPager.getAdapter().getCount();
					final int width = getWidth();
					final float halfWidth = width / 2f;
					final float sixthWidth = width / 6f;

					if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {
						if (action != MotionEvent.ACTION_CANCEL) {
							mViewPager.setCurrentItem(mCurrentPage - 1);
						}
						return true;
					} else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) {
						if (action != MotionEvent.ACTION_CANCEL) {
							mViewPager.setCurrentItem(mCurrentPage + 1);
						}
						return true;
					}
				}

				mIsDragging = false;
				mActivePointerId = INVALID_POINTER;
				if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag();
				break;

			case MotionEventCompat.ACTION_POINTER_DOWN: {
				final int index = MotionEventCompat.getActionIndex(ev);
				mLastMotionX = MotionEventCompat.getX(ev, index);
				mActivePointerId = MotionEventCompat.getPointerId(ev, index);
				break;
			}

			case MotionEventCompat.ACTION_POINTER_UP:
				final int pointerIndex = MotionEventCompat.getActionIndex(ev);
				final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
				if (pointerId == mActivePointerId) {
					final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
					mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
				}
				mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));
				break;
		}

		return true;
	}

	@Override
	public void setViewPager(ViewPager view) {
		if (mViewPager == view) {
			return;
		}
		if (mViewPager != null) {
			mViewPager.setOnPageChangeListener(null);
		}
		if (view.getAdapter() == null) {
			throw new IllegalStateException("ViewPager does not have adapter instance.");
		}
		mViewPager = view;
		mViewPager.setOnPageChangeListener(this);
		invalidate();
	}

	@Override
	public void setViewPager(ViewPager view, int initialPosition) {
		setViewPager(view);
		setCurrentItem(initialPosition);
	}

	@Override
	public void setCurrentItem(int item) {
		if (mViewPager == null) {
			throw new IllegalStateException("ViewPager has not been bound.");
		}
		mViewPager.setCurrentItem(item);
		mCurrentPage = item;
		invalidate();
	}

	@Override
	public void notifyDataSetChanged() {
		invalidate();
	}

	@Override
	public void onPageScrollStateChanged(int state) {
		mScrollState = state;

		if (mListener != null) {
			mListener.onPageScrollStateChanged(state);
		}
	}

	@Override
	public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
		mCurrentPage = position;
		mPageOffset = positionOffset;
		invalidate();
		if (mListener != null) {
			mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
		}
	}

	@Override
	public void onPageSelected(int position) {
		if (mSnap || mScrollState == ViewPager.SCROLL_STATE_IDLE) {
			mCurrentPage = position;
			mSnapPage = position;
			invalidate();
		}

		if (mListener != null) {
			mListener.onPageSelected(position);
		}
	}

	@Override
	public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
		mListener = listener;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see android.view.View#onMeasure(int, int)
	 */
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		if (mOrientation == HORIZONTAL) {
			setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec));
		} else {
			setMeasuredDimension(measureShort(widthMeasureSpec), measureLong(heightMeasureSpec));
		}
	}

	/**
	 * Determines the width of this view
	 *
	 * @param measureSpec A measureSpec packed into an int
	 * @return The width of the view, honoring constraints from measureSpec
	 */
	private int measureLong(int measureSpec) {
		int result;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
			//We were told how big to be
			result = specSize;
		} else {
			//Calculate the width according the views count
//            final int count = mRealCount;
			final int count = ((RecyleAdapter) mViewPager.getAdapter()).getRealCount();
			result = (int) (getPaddingLeft() + getPaddingRight()
					+ (count * 2 * mRadius) + (count - 1) * mRadius + 1);
			//Respect AT_MOST value if that was what is called for by measureSpec
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}

	/**
	 * Determines the height of this view
	 *
	 * @param measureSpec A measureSpec packed into an int
	 * @return The height of the view, honoring constraints from measureSpec
	 */
	private int measureShort(int measureSpec) {
		int result;
		int specMode = MeasureSpec.getMode(measureSpec);
		int specSize = MeasureSpec.getSize(measureSpec);

		if (specMode == MeasureSpec.EXACTLY) {
			//We were told how big to be
			result = specSize;
		} else {
			//Measure the height
			result = (int) (2 * mRadius + getPaddingTop() + getPaddingBottom() + 1);
			//Respect AT_MOST value if that was what is called for by measureSpec
			if (specMode == MeasureSpec.AT_MOST) {
				result = Math.min(result, specSize);
			}
		}
		return result;
	}

//    @Override
//    public void onRestoreInstanceState(Parcelable state) {
//        SavedState savedState = (SavedState)state;
//        super.onRestoreInstanceState(savedState.getSuperState());
//        mCurrentPage = savedState.currentPage;
//        mSnapPage = savedState.currentPage;
//        requestLayout();
//    }
//
//    @Override
//    public Parcelable onSaveInstanceState() {
//        Parcelable superState = super.onSaveInstanceState();
//        SavedState savedState = new SavedState(superState);
//        savedState.currentPage = mCurrentPage;
//        return savedState;
//    }
//
//    static class SavedState extends BaseSavedState {
//        int currentPage;
//
//        public SavedState(Parcelable superState) {
//            super(superState);
//        }
//
//        private SavedState(Parcel in) {
//            super(in);
//            currentPage = in.readInt();
//        }
//
//        @Override
//        public void writeToParcel(Parcel dest, int flags) {
//            super.writeToParcel(dest, flags);
//            dest.writeInt(currentPage);
//        }
//
//        @SuppressWarnings("UnusedDeclaration")
//        public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
//            @Override
//            public SavedState createFromParcel(Parcel in) {
//                return new SavedState(in);
//            }
//
//            @Override
//            public SavedState[] newArray(int size) {
//                return new SavedState[size];
//            }
//        };
//    }
}
